How to pin vue tree diagram to the top

Using tree diagrams in Vue projects is a common requirement, but in actual applications, we may encounter the problem that the tree diagram cannot be pinned to the top. This article will introduce how to solve this problem in Vue project.

1. Problem description

The Vue tree diagram component needs to be displayed at the top for some important nodes, but by default, the tree diagram nodes are arranged according to their position in the HTML code. . This will cause important nodes to be easily covered by other nodes when there are many nodes, affecting the user experience. Therefore, we need to solve the problem of how to pin these nodes to the top.

2. Solution

In the Vue project, we can solve the problem of sticking the tree map to the top through the following methods:

1. z-index attribute of CSS

The z-index attribute can control the stacking order of elements. The larger the value, the earlier the element is displayed. Therefore, we can set z-index values ​​for important nodes of the dendrogram to bring them to the top.

For example:

.tree-node-important {
    z-index: 9999;
}

2. Vue’s mounted life cycle function

Put the top code in the component in the mounted life cycle function. When the component is Executing after loading ensures that the tree nodes are ready when rendering, thereby avoiding the problem of position offset.

For example:

mounted() {
    // 将树节点置顶
    const importantNode = document.querySelector('.tree-node-important');
    importantNode.style.zIndex = '9999';
}

3. Code example

The following is an example of a tree diagram based on Vue.js and element-ui, in which .tree-node- The important class is the node class that needs to be pinned to the top. Pin it to the top in the mounted lifecycle function.

<template>
  <el-tree :data="treeData">
    <template v-slot="{node}">
      <span :class="{&#39;tree-node-important&#39;: node.important}">{{ node.label }}</span>
    </template>
  </el-tree>
</template>

<script>
export default {
  data() {
    return {
      treeData: [
        {
          label: '节点1',
          important: true,
          children: [
            {
              label: '节点1-1'
            },
            {
              label: '节点1-2'
            }
          ]
        },
        {
          label: '节点2',
          children: [
            {
              label: '节点2-1'
            },
            {
              label: '节点2-2'
            }
          ]
        }
      ]
    };
  },
  mounted() {
    // 将树节点置顶
    const importantNode = document.querySelector('.tree-node-important');
    importantNode.style.zIndex = '9999';
  }
};
</script>

<style scoped>
.tree-node-important {
  z-index: 9999;
}
</style>

4. Summary

In Vue projects, using tree diagram components is a common requirement. If we need to pin the tree diagram node to the top to ensure user experience, we can do this by setting the z-index attribute for the pinned node, or pin it to the top in the mounted lifecycle function. This method is simple and easy to implement and suitable for most Vue projects.

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